An ultra-secret clan of scientists and engineers who toiled in a gigantic enclave in Danbury, Conn., can finally reveal its covert activities. Declassified in September, project Hexagon launched the most successful spy satellite network of the Cold War and collected crucial data for decades that helped undermine the Soviet Union, reports the AP. From 1971 to 1986, more than 1,000 people worked grueling hours, speaking in code and denying the project's existence even to family members.
Used by the CIA and later the Air Force, the vastly ambitious and extremely clandestine mission sent 20 satellites into space, each equipped with 60 miles of film and cameras that orbited the Earth and spied on the Soviet Union, China, and other potential enemies. Among its triumphs: providing key information for the Strategic Arms Limitation Talks between the US and the Soviets in the 1970s. "It was intensely demanding, thrilling and the greatest experience of my life," one engineer says. (Read more Cold War stories.)